1.4.12: Text Spacing-New SC in the WCAG 2.1

Success Criterion 1.4.12 Text Spacing (Level AA): In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property:

  • Line height (line spacing) to at least 1.5 times the font size;
  • Spacing following paragraphs to at least 2 times the font size;
  • Letter spacing (tracking) to at least 0.12 times the font size;
  • Word spacing to at least 0.16 times the font size.

Exception: Human languages and scripts that do not make use of one or more of these text style properties in written text can conform using only the properties that exist for that combination of language and script.



There are certain group                 of low vision users, especially people who are suffering from Age-related Macular Degeneration, read the content on the web by customizing the original view. What does it mean? Let us understand this. Few low vision users feel very difficult to read the content on the web in it’s default view.  The reason is that block of text seems to be cluttered due to the small spacing for the low vision users and this makes it hard to read. To overcome this challenge, those low vision users use the stylesheets/extensions/bookmarklets  to make the same block of the text readable. You might be wondering what exactly these tools do. These tools enable the low vision user to adjust the spacing between characters/words/lines/paragraphs on the web and that intern helps the user’s readability. So far all is good and we understand that there are tools/assistive technologies that enables the low vision user to adjust the text spacing. However, when they try to adjust the text spacing via these tools then what if the text is cut off vertically, text is cut of horizontally, text is overlapped, and text is fixed. When we encounter such problems while using those tools then it is going to be problem for the low vision users to read the content on the web.

In order to address this problem, WCAG2.1 introduced this new success criterion. The intent of this Success Criterion (SC) is to ensure that people can override text spacing to improve their reading experience. Having said that, do you think user can adjust/override the text spacing to any extent. Answer is no. the success criterion clearly specifies that distances between paragraphs, lines, words and characters must be able to be increased to certain values without leading to loss of functionality or readability. The below are the specifications for the same.

  • Line height (line spacing) to at least 1.5 times the font size;
  • Spacing following paragraphs to at least 2 times the font size;
  • Letter spacing (tracking) to at least 0.12 times the font size;
  • Word spacing to at least 0.16 times the font size.


author responsibility

This SC does not dictate that authors must set all their content to the specified metrics. Rather, it specifies that an author’s content has the ability to be set to those metrics without loss of content or functionality. The author requirement is two-fold:

  • to not interfere with a user’s ability to override the author settings, and
  • to ensure that content modified to Success Criterion 1.4.12’s metrics does not break content.



  • People with low vision who require increased space between lines, words, and letters are able to read text.
  • People with dyslexia may increase space between lines, words, and letters to increase reading speed.
  • Although not required by this SC, white space between blocks of text can help people with cognitive disabilities discern sections and call out boxes. To put it more simpler, Many people with cognitive disabilities have trouble tracking lines of text when a block of text is single spaced. Providing spacing between 1.5 to 2 allows them to start a new line more easily once they have finished the previous one.


Pass scenarios

The below are the few scenarios where this success criterion is met

  • Spacing can be adjusted to the SC’s metrics
  • Text is not cut off in the both directions(horizontally and vertically)
  • Text is not overlapped
  • Plugin technologies that have a built-in ability to modify styles to the specified metrics.

Not applicable/exceptional  scenarios

This SC does not applicable for the below scenarios

  • PDF files as it is not implemented using markup
  • Video captions in the video player
  • Images of text that is built with canvas technology
  • There are cases where a text style property is not used in a language or script(e.g. applying word spacing for Japanese language would not have any effect as the language does not have words itself.

How to test this SC

Follow the below step by step instructions to test this SC

  1. Click Text Adaptation Bookmarklet – Steve Faulkner
  2. add the bookmarklet to the browser by following simple instructions that are given in the same link
  3. once the bookmarklet is added, open any web page
  4. navigate to browser bookmarks and activate “text spacing” bookmarklet
  5. the same web page displays with the SC metrics text spacing and check if the text is readable
  6. that is all you are done!


Here are the few techniques that author can use to meet this success criterion





2 Replies to “1.4.12: Text Spacing-New SC in the WCAG 2.1”

  1. Hi Suman,
    Your post is very helpful and easy to understand.
    I am not able to bookmark and activate “text spacing” bookmarklet.
    Could you please help me with that.

  2. Hi Geethika,
    ideally, it should work with the steps that is mentioned in the blog post. could you tell in which version and in which browser and in which environment you are trying?
    Thank you.

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